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linux-next/drivers/acpi/acpica/evgpeinit.c
Lv Zheng 0d0988af81 ACPICA: Events: Introduce ACPI_GPE_DISPATCH_RAW_HANDLER to fix 2 issues for the current GPE APIs 
ACPICA commit 199cad16530a45aea2bec98e528866e20c5927e1

Since whether the GPE should be disabled/enabled/cleared should only be
determined by the GPE driver's state machine:
1. GPE should be disabled if the driver wants to switch to the GPE polling
   mode when a GPE storm condition is indicated and should be enabled if
   the driver wants to switch back to the GPE interrupt mode when all of
   the storm conditions are cleared. The conditions should be protected by
   the driver's specific lock.
2. GPE should be enabled if the driver has accepted more than one request
   and should be disabled if the driver has completed all of the requests.
   The request count should be protected by the driver's specific lock.
3. GPE should be cleared either when the driver is about to handle an edge
   triggered GPE or when the driver has completed to handle a level
   triggered GPE. The handling code should be protected by the driver's
   specific lock.
Thus the GPE enabling/disabling/clearing operations are likely to be
performed with the driver's specific lock held while we currently cannot do
this. This is because:
1. We have the acpi_gbl_gpe_lock held before invoking the GPE driver's
   handler. Driver's specific lock is likely to be held inside of the
   handler, thus we can see some dead lock issues due to the reversed
   locking order or recursive locking. In order to solve such dead lock
   issues, we need to unlock the acpi_gbl_gpe_lock before invoking the
   handler. BZ 1100.
2. Since GPE disabling/enabling/clearing should be determined by the GPE
   driver's state machine, we shouldn't perform such operations inside of
   ACPICA for a GPE handler to mess up the driver's state machine. BZ 1101.

Originally this patch includes a logic to flush GPE handlers, it is dropped
due to the following reasons:
1. This is a different issue;
2. Linux OSL has fixed this by flushing SCI in acpi_os_wait_events_complete().
We will pick up this topic when the Linux OSL fix turns out to be not
sufficient.

Note that currently the internal operations and the acpi_gbl_gpe_lock are
also used by ACPI_GPE_DISPATCH_METHOD and ACPI_GPE_DISPATCH_NOTIFY. In
order not to introduce regressions, we add one
ACPI_GPE_DISPATCH_RAW_HANDLER type to be distiguished from
ACPI_GPE_DISPATCH_HANDLER. For which the acpi_gbl_gpe_lock is unlocked before
invoking the GPE handler and the internal enabling/disabling operations are
bypassed to allow drivers to perform them at a proper position using the
GPE APIs and ACPI_GPE_DISPATCH_RAW_HANDLER users should invoke acpi_set_gpe()
instead of acpi_enable_gpe()/acpi_disable_gpe() to bypass the internal GPE
clearing code in acpi_enable_gpe(). Lv Zheng.

Known issues:
1. Edge-triggered GPE lost for frequent enablings
   On some buggy silicon platforms, GPE enable line may not be directly
   wired to the GPE trigger line. In that case, when GPE enabling is
   frequently performed for edge-triggered GPEs, GPE status may stay set
   without being triggered.
   This patch may maginify this problem as it allows GPE enabling to be
   parallel performed during the process the GPEs are handled.
   This is an existing issue, because:
   1. For task context:
      Current ACPI_GPE_DISPATCH_METHOD practices have proven that this
      isn't a real issue - we can re-enable edge-triggered GPE in a work
      queue where the GPE status bit might already be set.
   2. For IRQ context:
      This can even happen when the GPE enabling occurs before returning
      from the GPE handler and after unlocking the GPE lock.
   Thus currently no code is included to protect this.

Link: https://github.com/acpica/acpica/commit/199cad16
Signed-off-by: Lv Zheng <lv.zheng@intel.com>
Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2015-02-05 15:34:51 +01:00

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/******************************************************************************
*
* Module Name: evgpeinit - System GPE initialization and update
*
*****************************************************************************/
/*
* Copyright (C) 2000 - 2015, Intel Corp.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions, and the following disclaimer,
* without modification.
* 2. Redistributions in binary form must reproduce at minimum a disclaimer
* substantially similar to the "NO WARRANTY" disclaimer below
* ("Disclaimer") and any redistribution must be conditioned upon
* including a substantially similar Disclaimer requirement for further
* binary redistribution.
* 3. Neither the names of the above-listed copyright holders nor the names
* of any contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* Alternatively, this software may be distributed under the terms of the
* GNU General Public License ("GPL") version 2 as published by the Free
* Software Foundation.
*
* NO WARRANTY
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
* IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGES.
*/
#include <acpi/acpi.h>
#include "accommon.h"
#include "acevents.h"
#include "acnamesp.h"
#define _COMPONENT ACPI_EVENTS
ACPI_MODULE_NAME("evgpeinit")
#if (!ACPI_REDUCED_HARDWARE) /* Entire module */
/*
* Note: History of _PRW support in ACPICA
*
* Originally (2000 - 2010), the GPE initialization code performed a walk of
* the entire namespace to execute the _PRW methods and detect all GPEs
* capable of waking the system.
*
* As of 10/2010, the _PRW method execution has been removed since it is
* actually unnecessary. The host OS must in fact execute all _PRW methods
* in order to identify the device/power-resource dependencies. We now put
* the onus on the host OS to identify the wake GPEs as part of this process
* and to inform ACPICA of these GPEs via the acpi_setup_gpe_for_wake interface. This
* not only reduces the complexity of the ACPICA initialization code, but in
* some cases (on systems with very large namespaces) it should reduce the
* kernel boot time as well.
*/
/*******************************************************************************
*
* FUNCTION: acpi_ev_gpe_initialize
*
* PARAMETERS: None
*
* RETURN: Status
*
* DESCRIPTION: Initialize the GPE data structures and the FADT GPE 0/1 blocks
*
******************************************************************************/
acpi_status acpi_ev_gpe_initialize(void)
{
u32 register_count0 = 0;
u32 register_count1 = 0;
u32 gpe_number_max = 0;
acpi_status status;
ACPI_FUNCTION_TRACE(ev_gpe_initialize);
ACPI_DEBUG_PRINT_RAW((ACPI_DB_INIT,
"Initializing General Purpose Events (GPEs):\n"));
status = acpi_ut_acquire_mutex(ACPI_MTX_NAMESPACE);
if (ACPI_FAILURE(status)) {
return_ACPI_STATUS(status);
}
/*
* Initialize the GPE Block(s) defined in the FADT
*
* Why the GPE register block lengths are divided by 2: From the ACPI
* Spec, section "General-Purpose Event Registers", we have:
*
* "Each register block contains two registers of equal length
* GPEx_STS and GPEx_EN (where x is 0 or 1). The length of the
* GPE0_STS and GPE0_EN registers is equal to half the GPE0_LEN
* The length of the GPE1_STS and GPE1_EN registers is equal to
* half the GPE1_LEN. If a generic register block is not supported
* then its respective block pointer and block length values in the
* FADT table contain zeros. The GPE0_LEN and GPE1_LEN do not need
* to be the same size."
*/
/*
* Determine the maximum GPE number for this machine.
*
* Note: both GPE0 and GPE1 are optional, and either can exist without
* the other.
*
* If EITHER the register length OR the block address are zero, then that
* particular block is not supported.
*/
if (acpi_gbl_FADT.gpe0_block_length &&
acpi_gbl_FADT.xgpe0_block.address) {
/* GPE block 0 exists (has both length and address > 0) */
register_count0 = (u16)(acpi_gbl_FADT.gpe0_block_length / 2);
gpe_number_max =
(register_count0 * ACPI_GPE_REGISTER_WIDTH) - 1;
/* Install GPE Block 0 */
status = acpi_ev_create_gpe_block(acpi_gbl_fadt_gpe_device,
acpi_gbl_FADT.xgpe0_block.
address,
acpi_gbl_FADT.xgpe0_block.
space_id, register_count0, 0,
acpi_gbl_FADT.sci_interrupt,
&acpi_gbl_gpe_fadt_blocks[0]);
if (ACPI_FAILURE(status)) {
ACPI_EXCEPTION((AE_INFO, status,
"Could not create GPE Block 0"));
}
}
if (acpi_gbl_FADT.gpe1_block_length &&
acpi_gbl_FADT.xgpe1_block.address) {
/* GPE block 1 exists (has both length and address > 0) */
register_count1 = (u16)(acpi_gbl_FADT.gpe1_block_length / 2);
/* Check for GPE0/GPE1 overlap (if both banks exist) */
if ((register_count0) &&
(gpe_number_max >= acpi_gbl_FADT.gpe1_base)) {
ACPI_ERROR((AE_INFO,
"GPE0 block (GPE 0 to %u) overlaps the GPE1 block "
"(GPE %u to %u) - Ignoring GPE1",
gpe_number_max, acpi_gbl_FADT.gpe1_base,
acpi_gbl_FADT.gpe1_base +
((register_count1 *
ACPI_GPE_REGISTER_WIDTH) - 1)));
/* Ignore GPE1 block by setting the register count to zero */
register_count1 = 0;
} else {
/* Install GPE Block 1 */
status =
acpi_ev_create_gpe_block(acpi_gbl_fadt_gpe_device,
acpi_gbl_FADT.xgpe1_block.
address,
acpi_gbl_FADT.xgpe1_block.
space_id, register_count1,
acpi_gbl_FADT.gpe1_base,
acpi_gbl_FADT.
sci_interrupt,
&acpi_gbl_gpe_fadt_blocks
[1]);
if (ACPI_FAILURE(status)) {
ACPI_EXCEPTION((AE_INFO, status,
"Could not create GPE Block 1"));
}
/*
* GPE0 and GPE1 do not have to be contiguous in the GPE number
* space. However, GPE0 always starts at GPE number zero.
*/
gpe_number_max = acpi_gbl_FADT.gpe1_base +
((register_count1 * ACPI_GPE_REGISTER_WIDTH) - 1);
}
}
/* Exit if there are no GPE registers */
if ((register_count0 + register_count1) == 0) {
/* GPEs are not required by ACPI, this is OK */
ACPI_DEBUG_PRINT((ACPI_DB_INIT,
"There are no GPE blocks defined in the FADT\n"));
status = AE_OK;
goto cleanup;
}
cleanup:
(void)acpi_ut_release_mutex(ACPI_MTX_NAMESPACE);
return_ACPI_STATUS(AE_OK);
}
/*******************************************************************************
*
* FUNCTION: acpi_ev_update_gpes
*
* PARAMETERS: table_owner_id - ID of the newly-loaded ACPI table
*
* RETURN: None
*
* DESCRIPTION: Check for new GPE methods (_Lxx/_Exx) made available as a
* result of a Load() or load_table() operation. If new GPE
* methods have been installed, register the new methods.
*
******************************************************************************/
void acpi_ev_update_gpes(acpi_owner_id table_owner_id)
{
struct acpi_gpe_xrupt_info *gpe_xrupt_info;
struct acpi_gpe_block_info *gpe_block;
struct acpi_gpe_walk_info walk_info;
acpi_status status = AE_OK;
/*
* Find any _Lxx/_Exx GPE methods that have just been loaded.
*
* Any GPEs that correspond to new _Lxx/_Exx methods are immediately
* enabled.
*
* Examine the namespace underneath each gpe_device within the
* gpe_block lists.
*/
status = acpi_ut_acquire_mutex(ACPI_MTX_EVENTS);
if (ACPI_FAILURE(status)) {
return;
}
walk_info.count = 0;
walk_info.owner_id = table_owner_id;
walk_info.execute_by_owner_id = TRUE;
/* Walk the interrupt level descriptor list */
gpe_xrupt_info = acpi_gbl_gpe_xrupt_list_head;
while (gpe_xrupt_info) {
/* Walk all Gpe Blocks attached to this interrupt level */
gpe_block = gpe_xrupt_info->gpe_block_list_head;
while (gpe_block) {
walk_info.gpe_block = gpe_block;
walk_info.gpe_device = gpe_block->node;
status = acpi_ns_walk_namespace(ACPI_TYPE_METHOD,
walk_info.gpe_device,
ACPI_UINT32_MAX,
ACPI_NS_WALK_NO_UNLOCK,
acpi_ev_match_gpe_method,
NULL, &walk_info, NULL);
if (ACPI_FAILURE(status)) {
ACPI_EXCEPTION((AE_INFO, status,
"While decoding _Lxx/_Exx methods"));
}
gpe_block = gpe_block->next;
}
gpe_xrupt_info = gpe_xrupt_info->next;
}
if (walk_info.count) {
ACPI_INFO((AE_INFO, "Enabled %u new GPEs", walk_info.count));
}
(void)acpi_ut_release_mutex(ACPI_MTX_EVENTS);
return;
}
/*******************************************************************************
*
* FUNCTION: acpi_ev_match_gpe_method
*
* PARAMETERS: Callback from walk_namespace
*
* RETURN: Status
*
* DESCRIPTION: Called from acpi_walk_namespace. Expects each object to be a
* control method under the _GPE portion of the namespace.
* Extract the name and GPE type from the object, saving this
* information for quick lookup during GPE dispatch. Allows a
* per-owner_id evaluation if execute_by_owner_id is TRUE in the
* walk_info parameter block.
*
* The name of each GPE control method is of the form:
* "_Lxx" or "_Exx", where:
* L - means that the GPE is level triggered
* E - means that the GPE is edge triggered
* xx - is the GPE number [in HEX]
*
* If walk_info->execute_by_owner_id is TRUE, we only execute examine GPE methods
* with that owner.
*
******************************************************************************/
acpi_status
acpi_ev_match_gpe_method(acpi_handle obj_handle,
u32 level, void *context, void **return_value)
{
struct acpi_namespace_node *method_node =
ACPI_CAST_PTR(struct acpi_namespace_node, obj_handle);
struct acpi_gpe_walk_info *walk_info =
ACPI_CAST_PTR(struct acpi_gpe_walk_info, context);
struct acpi_gpe_event_info *gpe_event_info;
u32 gpe_number;
char name[ACPI_NAME_SIZE + 1];
u8 type;
ACPI_FUNCTION_TRACE(ev_match_gpe_method);
/* Check if requested owner_id matches this owner_id */
if ((walk_info->execute_by_owner_id) &&
(method_node->owner_id != walk_info->owner_id)) {
return_ACPI_STATUS(AE_OK);
}
/*
* Match and decode the _Lxx and _Exx GPE method names
*
* 1) Extract the method name and null terminate it
*/
ACPI_MOVE_32_TO_32(name, &method_node->name.integer);
name[ACPI_NAME_SIZE] = 0;
/* 2) Name must begin with an underscore */
if (name[0] != '_') {
return_ACPI_STATUS(AE_OK); /* Ignore this method */
}
/*
* 3) Edge/Level determination is based on the 2nd character
* of the method name
*/
switch (name[1]) {
case 'L':
type = ACPI_GPE_LEVEL_TRIGGERED;
break;
case 'E':
type = ACPI_GPE_EDGE_TRIGGERED;
break;
default:
/* Unknown method type, just ignore it */
ACPI_DEBUG_PRINT((ACPI_DB_LOAD,
"Ignoring unknown GPE method type: %s "
"(name not of form _Lxx or _Exx)", name));
return_ACPI_STATUS(AE_OK);
}
/* 4) The last two characters of the name are the hex GPE Number */
gpe_number = ACPI_STRTOUL(&name[2], NULL, 16);
if (gpe_number == ACPI_UINT32_MAX) {
/* Conversion failed; invalid method, just ignore it */
ACPI_DEBUG_PRINT((ACPI_DB_LOAD,
"Could not extract GPE number from name: %s "
"(name is not of form _Lxx or _Exx)", name));
return_ACPI_STATUS(AE_OK);
}
/* Ensure that we have a valid GPE number for this GPE block */
gpe_event_info =
acpi_ev_low_get_gpe_info(gpe_number, walk_info->gpe_block);
if (!gpe_event_info) {
/*
* This gpe_number is not valid for this GPE block, just ignore it.
* However, it may be valid for a different GPE block, since GPE0
* and GPE1 methods both appear under \_GPE.
*/
return_ACPI_STATUS(AE_OK);
}
if ((ACPI_GPE_DISPATCH_TYPE(gpe_event_info->flags) ==
ACPI_GPE_DISPATCH_HANDLER) ||
(ACPI_GPE_DISPATCH_TYPE(gpe_event_info->flags) ==
ACPI_GPE_DISPATCH_RAW_HANDLER)) {
/* If there is already a handler, ignore this GPE method */
return_ACPI_STATUS(AE_OK);
}
if (ACPI_GPE_DISPATCH_TYPE(gpe_event_info->flags) ==
ACPI_GPE_DISPATCH_METHOD) {
/*
* If there is already a method, ignore this method. But check
* for a type mismatch (if both the _Lxx AND _Exx exist)
*/
if (type != (gpe_event_info->flags & ACPI_GPE_XRUPT_TYPE_MASK)) {
ACPI_ERROR((AE_INFO,
"For GPE 0x%.2X, found both _L%2.2X and _E%2.2X methods",
gpe_number, gpe_number, gpe_number));
}
return_ACPI_STATUS(AE_OK);
}
/* Disable the GPE in case it's been enabled already. */
(void)acpi_hw_low_set_gpe(gpe_event_info, ACPI_GPE_DISABLE);
/*
* Add the GPE information from above to the gpe_event_info block for
* use during dispatch of this GPE.
*/
gpe_event_info->flags &= ~(ACPI_GPE_DISPATCH_MASK);
gpe_event_info->flags |= (u8)(type | ACPI_GPE_DISPATCH_METHOD);
gpe_event_info->dispatch.method_node = method_node;
ACPI_DEBUG_PRINT((ACPI_DB_LOAD,
"Registered GPE method %s as GPE number 0x%.2X\n",
name, gpe_number));
return_ACPI_STATUS(AE_OK);
}
#endif /* !ACPI_REDUCED_HARDWARE */
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